IMO, For a watch, priority always goes to the glass. As long as there is an option for sapphire glass and the cost is affordable. I personally will go for that option. Scratches on the SS won't affect me, but a single scratch on the glass will make me feel very annoying.
Only after that, if I still have choices, then I will consider the material of the watch body.
In this case, Sapphire makes the Sports not in my shopping list anymore. Then the choice between gold and SS is very easy for me. SS!
Last but not least, coating or not coating. Again, if available, always go for the coating. If Apple do it right, the coating should give the watch a very good resistance to scratch. So, my 1st choice is the black SS. Can I afford it? Yes, then it become my final choice.
Anyway, I have a 38mm M loop in hand now, which arrived on 24th. That's belongs to my daughter, she's just 5yrs old. Obviously she won't over protect the watch. That watch still looks like new now. No crazy scratches, at least I can't see anything in normal distance and lighting. SS will scratch from time to time, but it's just normal SS, not particularly bad SS. I don't think you need to worry about that too much.